Ranked 97th among 1,645 people around the globe whose net worth this month exceeds US$1 billion, Dhanin is the richest Thai with net worth of $11.4 billion. Last year, he was ranked 58th with net worth of $14.3 billion - which was the highest level since 2009 when he first joined the ranking.

Also on the list are Charoen Sirivadhanabhakdi, Vanich Chaiyawan, Krit Ratanarak, Prasert Prasarttong-Osoth and Keeree Kanjanapas. The magazine also put Thaksin Shinawatra and family on the list, with net worth of $1.6 billion. It said that "ousted in a 2006 coup, Thaksin managed to recover close to $1 billion of his $2.3 billion in frozen assets".

The rest are Vichai Srivaddhanaprabha, Surin Upatkoon and Thongma Vijitpongpun. Aloke Lohia, chief of Indorama Ventures, was the last on the list with net worth of $1.1 billion.

Globally, Bill Gates is back on top after a four-year hiatus, reclaiming the title of world's richest person from telecom mogul Carlos Slim Helu of Mexico. Gates saw his fortune rise by $9 billion in the past year to $76 billion.

Forbes found 1,645 billionaires with an aggregate net worth of $6.4 trillion, up from $5.4 trillion a year ago. Among them, 268 were new 10-figure fortunes, including 42 new female billionaires, another record. In total, there are 172 women on the list, more than ever before and up from 138 last year.

Thanks to the technology boom and strong stock market, the United States once again leads the world with 492 billionaires, followed by China with 152 and Russia with 111. But wealth is spreading to new places. Forbes found billionaires for the first time in Algeria, Lithuania, Tanzania and Uganda.